<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        .box {
            position: relative;
            width: 500px;
            height: 500px;
            margin: 100px auto;
            border-radius: 50%;
            border: 2px solid #eee;
            background-color: #001;
            background-image: radial-gradient(white 15%, transparent 16%);
            background-size: 60px 60px;
        }
        
        .shadow {
            position: absolute;
            /* top: 50%; */
            /* left: 50%; */
            /* margin-left: -220px; */
            /* margin-top: -220px; */
            width: 500px;
            height: 500px;
            border-radius: 50%;
            background-image: radial-gradient( transparent 60%, rgba(255, 255, 255, 0.3) 15%);
        }
    </style>
</head>

<body>
    <div class="box">
        <div class="shadow"></div>
    </div>
</body>

</html>